1. Field of the Invention
The present invention relates in general to diagnosing systems for diagnosing a control device of a vehicle-mounted equipment, and more particularly to the diagnosing systems of a type that diagnoses a memory of the control device of the vehicle-mounted equipment.
2. Description of the Related Art
Hitherto, in the field of motor vehicles, various diagnosing systems for diagnosing a control device of a vehicle-mounted equipment have been proposed and put into practical use. One of them is disclosed in Japanese Laid-open Patent Application (tokkai) 2003-26024.
The diagnosing system disclosed by the publication is a system that diagnoses a control device of a power steering device mounted on a wheeled motor vehicle. The diagnosing system of the publication comprises a primary microcomputer and a secondary microcomputer between which various data signals are transmitted under operation. That is, one of the microcomputers that is serving as a data receiving computer judges whether a data receiving is regularly or normally made or not, and if the data receiving is not regularly or normally carried out, judgment is so made that the other microcomputer has a trouble. Furthermore, when, upon diagnosing the received data, the microcomputer serving as the data receiving computer finds that the data is abnormal, judgment is so made that the other microcomputer has a trouble.